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Lee ultimate dies ( new style- black bottom case)

26 Oct 2020
@ 02:39 pm (GMT)

David Kopp

I been using these dies and just started with the neck sizing. I notice when using the neck die it leaves the tip of the case in sized and looks flared but is not. Appeartly, they chose to do this due to customer feed back. So, when I apply more pressure the more the flare is this ok or am I missing how to use this die or would I need to sand down the stem as per Nathan's book says to. I do notice neck tension is less than the fl die or do I go neck size and use the crimp die to compensate? Uggh, I'm prolly thinking to much. I hope this can help others as well, thanks.


28 Oct 2020
@ 04:08 am (GMT)

Paul Leverman

Re: Lee ultimate dies ( new style- black bottom case)
David, something doesn't sound right. You may want to contact Lee Precision. Out of curiosity, I pulled my neck sizer apart, and I don't see anything that would account for a flare. I'd check with Lee, they are excellent at customer service.
28 Oct 2020
@ 11:14 am (GMT)

David Kopp

Re: Lee ultimate dies ( new style- black bottom case)
Here is a copy from Lee precision for there collect neck size die;

" If you’re a long-time user of Lee Collet Neck Sizing Die you may notice we have modified the Collet so a small portion of the neck protrudes through the end of the Collet-Sizing portion. This often-requested modification was implemented in 2019.

This change allows the portion of the neck that protrudes above the Collet to remain in its fire formed condition. This provides a natural flare to the case neck allowing easy and concentric seating of bullets. This is especially important when seating cast bullets or low drag coated bullets.

Noted author and cartridge designer M. L. McPherson has suggested this modification for years for its ease of use, better function and improved accuracy." If you go to there web page they show a cut out of what there talking about.

The only thing bugging me is when I use extra force the flare is more pronounce and was wondering to maybe looking into the undersized stem for the die. Sorry, if I sounded confusing. I think I'm getting decent results with how I'm using the die, I know I have to work on maintaining the same pressure when using the collect. Meaning, neck tension is light when I use the 25# method of Nathan's and when I used extra force the flare is more which makes sense as long as this does not create other issues.

Im using it for 308 with Winchester brass, maybe this is my issue cause win brass is thinner walled?
Thanks for reply Paul

28 Oct 2020
@ 12:19 pm (GMT)

Paul Leverman

Re: Lee ultimate dies ( new style- black bottom case)
Well, I guess my dies are previous to the change. They must know what they are doing and why. Seems a little weird to me, but I'm a dinosaur who doesn't like change.

Is the flare measurable? How long is it? Or is it just that last couple of thousandths at the end? What happens when you run a loaded round up into the crimp die? Can you feel it? And does it interfere with the crimp?

Sorry for all the questions, but if this design is going to be the normal, I might start looking to buy older die sets at the gun shows.

28 Oct 2020
@ 12:33 pm (GMT)

Paul Leverman

Re: Lee ultimate dies ( new style- black bottom case)
Interestingly, Lee also gives you this
01 Nov 2020
@ 09:55 am (GMT)

David Kopp

Re: Lee ultimate dies ( new style- black bottom case)
Hey Paul, I measured its about a 1mm (.040”) and flare goes away with using the crimp die with ease. It did seem more noticeable to use more pressure to make a tighter crimp, thats without a crimp ring on bullet.
I guess it is easier the seat the bullet but not sure if it adds to concentricity. Will need to test if crimping aids meaningful bonus to the load development.

Hope this helps and sorry for my tardiness.
02 Nov 2020
@ 03:12 am (GMT)

Paul Leverman

Re: Lee ultimate dies ( new style- black bottom case)
Hi David. I just looked at my dies again, and the sized cases that came out of them. Apparently, the change was made after mine were purchased. I also tried some flat based bullets just to see how much effort was required to start them. Maybe it's because I use more taper/chamfer than others, but I didn't notice any difference. Could be that this complaint came from the users with those multiple station loading presses. What if a guy didn't use the factory crimp die afterwards? Would the cases that are flared chamber ok? I think I'd go back and resize everything with the washer as Lee suggested. This is why I don't get along with change and technology.
10 Nov 2020
@ 07:41 am (GMT)

David Kopp

Re: Lee ultimate dies ( new style- black bottom case)
Hey Paul, not sure why the complaint from customers, the flared case does allow for easy bullet seating. Maybe it leads to less tapering/chamfering for that ease and speed in those presses. Leaning Nathan's way of case prep will still be my go to.

The cases load fine into the rifle because the case mouth is not expanded more than the chamber. It just looks off/different than the usual handloads.

I have used it without the crimp accuracy was ok but I think the neck tension needs to be more consistent. I will need to use the shim method to see if there's a change in chambering.

Hope this helped Paul, yeah change can be good or bad guess it's how we see it.


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